Acquiring accurate nucleic acid sequence information in a rapid and cost-effective manner is essential for the modern era of genomic analysis. Certain automated DNA sequencing platforms require iterative cycles of enzyme-based nucleotide binding, incorporation into an extending primer, detection of incorporation reaction products, and even chemical modification of the extended primer to render it useful in a subsequent cycle. Repeating the cycle for up to four candidate nucleotides to identify the cognate nucleotide at a single position along a DNA template complicates the workflow, and increases reagent costs.
Stretches of more than one of the same base along a strand of nucleic acid are among factors confounding accurate sequence determination. These “homopolymer” stretches can be overlooked by some sequencing approaches, such that a single base will be detected when multiples actually are present. Some sequencing methods further can experience “phasing” issues that can be promoted by the presence of homopolymer stretches. As a consequence of phasing, sequence determination downstream of the homopolymer stretch can be rendered ambiguous.
Despite the many advances reported in the field of nucleic acid sequencing technology, there remains a need for improved systems that deliver accurate results quickly.